藏南甲岗—定结裂谷现今变形特征的GPS&InSAR监测及其构造意义

近南北向的裂谷带(地堑)是藏中南地区最显著的构造现象之一，既是对印度与欧亚大陆汇聚的变形调节，也与青藏高原隆生、构造块体运动、强震孕育等密切相关。但由于定量化描述断层活动的地震地质、大地测量数据不足,对藏南裂谷带在第四纪青藏高原南北向缩短、东西向伸展变形过程中的调节作用仍认识有限，其与周边活动断层在空间上的运动学关系也模糊不清。本研究拟以甲岗—定结裂谷为突破口，在原有GNSS观测资料的基础上，通过进一步加密布点、观测，建立数条跨断层的地壳位移速度剖线，并融合InSAR资料，精确测定断层各段滑动速率、几何学特征、应力分配样式，以及相邻活动地块的旋转、应变幅度，明确该断裂带构造活动特征及其与强震的关系。同时，研究断层在吸收、转换印度-欧亚板块汇聚中的具体作用，揭示藏南裂谷带在青藏高原构造演化中的地位、以及与新生代地壳增厚、隆升的关系。

The SN-trending rifts (graben) distribution is one of the most remarkable tectonic landforms in the southern Tibet. These rifts not only regulate the deformation of the India-Eurasia Collision, but also closely related to the uplift , tectonic block movements and strong earthquakes of the Tibet Plateau. However, due to the lack of quantitative seismic geology and geodesy data describing fault activity, there is still a limited understanding in the regulating role of those faults how to shorten along SN and how to extend along WE within the plateau, and the spatial kinematic relationship between the rift zone and the surrounding active faults is even more unclear. In this study, we take the Jiagang-Dingjie rift as a breakthrough point. On the basis of the GNSS data that we have got, we further expect to densify the existed GPS network and form several crustal displacement velocity profiles across the fault, and then we will integrate the GPS and InSAR data to derive the slip rate and geometric characteristics of different segments of the rift, the stress distribution methods, the rotation and motion range of the adjacent blocks, etc. Then, we will investigate the relationship between crustal deformation features and strong earthquakes. Finally, we will try to discuss how the rift act in the India-Eurasia Collision，reveal the role of rift in central and southern Tibet played in the evolution of Tibet Plateau and its relationship with the crustal thickening and uplifting in the Cenozoic.